[hyena] Add HYENA_MD5 method

[Gabriel Burt <gburt src gnome org>]

commit 1244ddfd34eb8364bd072a4e83adcb1470159f5c
Author: Gabriel Burt <gabriel burt gmail com>
Date:   Thu May 13 16:35:57 2010 -0700

    Add HYENA_MD5 method
    
    Available in SQL statements; first arg is the # of args, and the
    following are objects that will be added to a StringBuffer and MD5'd.

 .../Hyena.Data.Sqlite/SqliteUtils.cs               |   14 ++++++++++++++
 1 files changed, 14 insertions(+), 0 deletions(-)
---
diff --git a/src/Hyena.Data.Sqlite/Hyena.Data.Sqlite/SqliteUtils.cs b/src/Hyena.Data.Sqlite/Hyena.Data.Sqlite/SqliteUtils.cs
index 979ccb3..31a8626 100644
--- a/src/Hyena.Data.Sqlite/Hyena.Data.Sqlite/SqliteUtils.cs
+++ b/src/Hyena.Data.Sqlite/Hyena.Data.Sqlite/SqliteUtils.cs
@@ -194,4 +194,18 @@ namespace Hyena.Data.Sqlite
             return Hyena.StringUtil.SearchKey (args[0] as string);
         }
     }
+
+    [SqliteFunction (Name = "HYENA_MD5", FuncType = FunctionType.Scalar, Arguments = -1)]
+    internal class Md5Function : SqliteFunction
+    {
+        public override object Invoke (object[] args)
+        {
+            int n_args = (int)(long) args[0];
+            var sb = new StringBuilder ();
+            for (int i = 1; i <= n_args; i++) {
+                sb.Append (args[i]);
+            }
+            return Hyena.CryptoUtil.Md5Encode (sb.ToString (), System.Text.Encoding.UTF8);
+        }
+    }
 }